These are some cheesy dancing letter GIFs. They were probably made in the
90's or early 2000's. The creator of them is shrouded in mystery. One
thing's for sure, though - they're not me! These red characters with arms 
and legs have appeared around all corners of the internet since then.

These GIFs can be seen in some internet memes. An
example is https://invidio.us/watch?v=4W9QJcx5nsw *

* If you don't understand it, it's basically an ironic version of 'LOL SO
RANDOM'

I retrieved these letters from http://dance.cavifax.com/. You can use them
freely without any permission or attribution... practically. Technically,
the GIFs are still under copyright law, but come on, nobody's getting sued
for using them :)

~mayhair

Update (Feb 14, 2020): Added gifs for digits (e.g. 0, 1) and miscellaneous
characters (e.g. dollar sign, question mark).